The idea that cholesterol is the cause of the vascular damage seen in the aetiology of atherosclerosis is outdated. The original theory suggested that cholesterol from the diet could cause an increase in the cholesterol levels of the blood, and this in turn resulted in the production of atherosclerotic plaques, which contained cholesterol. The theory sounded plausible on the surface which is why it was easy to convince most of the population of the Western nations that a serious regimen of low cholesterol foods would cure the epidemic of cardiovascular disease that was beginning to peak in these countries. However, there was one major flaw in the theory, and that was the science did not show any solid evidence for any part of the chain of evidence. For example, the evidence to date suggests that dietary cholesterol is not able to cause increases in plasma levels of cholesterol, and lowering cholesterol levels does not cause regression of atherosclerotic plaques and improve vascular function.
For example, in a recent study, researchers investigated the effects of consuming low fat spreads with added plant sterols on the vascular function of subjects with high blood cholesterol1. Plant sterols have been previously shown to lower plasma cholesterol levels. Subjects consumed 20 grams of low fat spread without or with added plant sterols for 12 weeks and the changes to their vascular function were measured. As expected the consumption of the low fat spread with plant sterols caused a reduction in the plasma low density lipoprotein (LDL) cholesterol fraction of the blood. as has previously been shown. However, there was no improvement in the vascular function, as measured through flow mediated dilation, to accompany this fall. Both plasma campesterol and sitosterol, two of the plant sterols used in the spread, increased in those subjects consuming the spread suggesting that the fall in LDL levels was caused by the plant sterols. Therefore plant sterols lower blood cholesterol levels but do not affect vascular function.
This is a similar picture as seen with the statin drugs, which are effective cholesterol lowering agents, but which do little to improve the health of those talking them, in many cases actually causing increased mortality in suicide, accidents and violent death. This is because high cholesterol levels are not the cause of cardiovascular disease but a symptom. High cholesterol levels are associated with the disease, but not its cause. The cause of cardiovascular disease is likely development of insulin resistance and the metabolic syndrome, a condition that centres on the dysfunction to the liver. This dysfunction also causes changes to lipid metabolism including modification of plasma cholesterol levels, the liver being the main organ of synthesis and metabolism of cholesterol. Further, the safety of plant sterols has not been established. Effective cardiovascular disease treatment involves treating the underlying insulin resistant state through a high quality diet comprising of plant foods that sensitise the insulin system.
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